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if a header makes you run super lean, then yes the headers adds power because it along with the the car running leaner added power.

Thing is, you don't need to change headers to get leaner. You could just change the tune, and save yourself the cost of the header.

It could be that the header gained no power other than what you'd gain by tweaking the tune and using the original header. I am not claiming that this is the case - in fact I really like the design of this header - I am just saying that this experiment doesn't provide evidence that the header enabled the car to make more more power than simply retuning.

And I'm still really confused about why changing a header would cause the car to run leaner in the first place anyway. Like I said earlier, if there's more air going through the motor, there's more air going past the MAF sensor, so the ECU would be adding more fuel accordingly. It looks like something else changed, not just the header.

Thing is, you don't need to change headers to get leaner. You could just change the tune, and save yourself the cost of the header.

It could be that the header gained no power other than what you'd gain by tweaking the tune and using the original header. I am not claiming that this is the case - in fact I really like the design of this header - I am just saying that this experiment doesn't provide evidence that the header enabled the car to make more more power than simply retuning.

And I'm still really confused about why changing a header would cause the car to run leaner in the first place anyway. Like I said earlier, if there's more air going through the motor, there's more air going past the MAF sensor, so the ECU would be adding more fuel accordingly. It looks like something else changed, not just the header.

thats why i said power was added "along" with the header and it was leaner.

while im tired and cant say for sure, but the OEM header is very small, restrictive and a horrible design!! any aftermarket header including this one would forsure make the car run leaner. more air flow period. can the MAF make corrections to add more fuel? yes but not much when your talking that much more flow.

can the MAF make corrections to add more fuel? yes but not much when your talking that much more flow.

:facepalm:

Actually, yes. Just yes. Note "yes, but..."

Just yes. That is what MAF-based fueling is all about.

The MAF sensor's job is to let the ECU know how much air is flowing into the motor. If it can't do that accurately, something's really f***ed up. The tune either needs a MAF scaling adjustment, or (and I really doubt this was the case here...) the MAF sensor needs to be put into a bigger housing.

Nsfw is right. And the thing is that the tuners/shops doing this chit should know what parameters to look at. But they don't and I can't recall any header test done on here with mafv plots (except mine, which wasn't a header test).

Its really easy to tune a car conservatively on one part then add 1* of timing on another part and pick up 10whp. So pretty much all results are skeptical to me unless all the data is posted.

You guys are looking at what I've stated here with the 2 shops and thier comparisons so I restate the jist.

Epic Motorsport performed a before/after test with OTS (Off The Shelf) Cobb maps to see what would happen, since this if fairly common as not everyone gets tuned. When that was done they tuned the car and that plot is shown as well, it's the one that says Stage II tune vs. Epic Motorsport Custom Tune.

EFI Logics tested the header (FULL REVIEW HERE) on a tuned car then swapped only the header and retuned. They included all kinds of graphs and data logs.

IMO the data from both is relevant because it shows what happens if I have a COBB OTS stage II car and I put on the Killer B Header, as well as what you can expect if you have an already tuned car and and what to add our header.

I'm working on collecting some more data, but it takes time. Unlike most manufacturers we're offering our data, collected by other shops, in a public forum. Good or bad it lets the consumer make a more informed decision. It's a better than the typical "expect midrange power increase" with our header. Right?

Phatron, check out EFI's review/data, and by all means call the sources of these tests. Chris at EFI Logics and/or Robbie at Epic Motorsports can answer any questions you have. I'm a mechanical engineer not a tuner, so they can much better answer your questions and they have no vested interest in selling headers.

The MAF sensor's job is to let the ECU know how much air is flowing into the motor. If it can't do that accurately, something's really f***ed up. The tune either needs a MAF scaling adjustment, or (and I really doubt this was the case here...) the MAF sensor needs to be put into a bigger housing.

this kinda contradicts its self. your saying the MAF can make the corrections and thats it! but then you say the tuner needs to adjust scaling. so ill hold what i said first. the MAF can adjust BUT not much! thats why you cant throw in 1000cc injectors and be ok. why you cant add a CAI, DP, header, UP CBE and be ok. i put on a CAI with no adjustment and shot up to 33MPG. the car was WAY to lean. the AFR and scaling still needs adjusted because the MAF CANT do it all.

this kinda contradicts its self. your saying the MAF can make the corrections and thats it! but then you say the tuner needs to adjust scaling. so ill hold what i said first. the MAF can adjust BUT not much! thats why you cant throw in 1000cc injectors and be ok. why you cant add a CAI, DP, header, UP CBE and be ok. i put on a CAI with no adjustment and shot up to 33MPG. the car was WAY to lean. the AFR and scaling still needs adjusted because the MAF CANT do it all.

You're missing the point. Putting in larger injectors changes the fuel flow characteristics of the system, not the airflow. Putting in a CAI changes the MAF scaling, thereby throwing off the MAF sensor. If the intake and fuel systems are kept consistent, and no leaks are presented, the resulting a/f SHOULD be very close barring issues with the tune.

The flip side of this, however, is VE. The MAF is not the end all, be all of fueling in the ECU. The ECU receives the MAF signal, uses the calibration table to convert it to an airflow value, and then uses this airflow value along with injector calibration values, trim tables, and VE calibration data to calculate the required injector on-time to achieve the desired a/f target. So if we are indeed keeping the fuel system and intake system consistent and leak free, and the tune is set up properly to handle the given range of airflows, a change in VE could still result in a shift in a/f. This is because VE defines how efficiently the engine uses the air that it consumes. If you increase VE and keep all other parameters consistent (including airflow), you will inherently see a shift in the a/f.

The problem is that its very difficult to say which inconsistency caused the a/f swing without doing an extensive pressurized leak test of the exhaust and intake systems. Now, if indeed a VE change is the actual cause of the a/f swing, its even more necessary to fully tune both setups individually to present actual gains from the part since a change in VE can call for very different ignition advance, cam advance, and a/f profiles.

So the question remains, what happens if you switch headers and don't change AFR?

He actually has both cases covered.

The EFI test was tuned with 1 header vs. tuned with the other header and AFR is right in line in both cases.

The Epic test shows a real world expectation from someone adding headers to an existing map, since they stated Cobb OTS stage 2 maps in both cases.

Both have their place, as both are realistic expectations for what a customer would do. A customer will either add the header and re-tune or a customer will add a header and not retune. The useful information is that there is a gain in both cases, but there is some danger in adding the header and not retuning, since AFR seems to lean out as a result. This is all very good and useful information to have.

Science is an interesting thing because one person's idea of what "holding everything else constant" means is different from another. For example, I don't think holding AFR constant is the correct way to do a "only one thing changes" comparison. It is possible for exhaust modifications to change EGTs at a given AFR, and would argue that if the header allows for cooler EGT at a given AFR, then EGT should be raised some by leaning AFR to create an "equal" margin situation.

I think KillerB has gone to greater lengths than most manufacturers to quantify the benefits of his product. I think there is enough information available that an educated potential customer can see the tests are reasonably well done. Perhaps not perfect but there is enough information available to demonstrate there are genuine power gains to be had in the upper RPMs from the product.

Its really easy to tune a car conservatively on one part then add 1* of timing on another part and pick up 10whp. So pretty much all results are skeptical to me unless all the data is posted.

While this is certainly possible, when a tuner like epic or EQ or Jorge or GST or you/Mikey or EFI or another well respected tuner says it's a Cobb OTS Stage 2 map in both cases, I pretty much believe them that it's a Cobb OTS Stage 2 map in both cases and this implies there is no timing changes.

Why would you want to hack up a header that's specifically designed for OEM location when there are already several headers out there designed specifically for monster rotated turbo setups? I'm uncertain of the validity of any testing since it wouldn't be performed on a rotated setup.

I wouldn't be 'hacking up' for my use nor would 'monster' manifolds be ideal. It would be a simple v-band and a 30R for a dd wagon.

I have no issue waiting for your personal manifold for testing. I'd really like to see and compare runner lengths and diameters of the primaries, secondaries (where applicable) and then collectors and then see how they compare on the dyno. Noting that your manifold is the only 4-1 manifold of the group and is noted to be performing so well.

My only angle is I'm really searching for a base manifold to chop up for a nice rotated setup, i.e. who's getting my money

But you said^

Quote:

Originally Posted by Homemade WRX

I'd really like to see and compare runner lengths and diameters of the primaries, secondaries (where applicable) and then collectors and then see how they compare on the dyno. Noting that your manifold is the only 4-1 manifold of the group and is noted to be performing so well.

And this makes me wonder too, since you are 3MI Racing LLC. It almost sounds like you're angling to make your own product, possibly piggybacking on the design we've been working on for a good portion of this past year (patent pending BTW). If I'm mistaken here I apoligize, and please feel free to set me straight on your intentions.

I took it as he was going to test 4-5 different headers, compare dimensions, and use the best one and make a rotated up pipe for it.......he wants to use a v-band connection so the flange would have to be hacked off all the headers with standard 2-3 bolt flanges.....

You guys are looking at what I've stated here with the 2 shops and thier comparisons so I restate the jist.

Epic Motorsport performed a before/after test with OTS (Off The Shelf) Cobb maps to see what would happen, since this if fairly common as not everyone gets tuned. When that was done they tuned the car and that plot is shown as well, it's the one that says Stage II tune vs. Epic Motorsport Custom Tune.

EFI Logics tested the header (FULL REVIEW HERE) on a tuned car then swapped only the header and retuned. They included all kinds of graphs and data logs.

IMO the data from both is relevant because it shows what happens if I have a COBB OTS stage II car and I put on the Killer B Header, as well as what you can expect if you have an already tuned car and and what to add our header.

I'm working on collecting some more data, but it takes time. Unlike most manufacturers we're offering our data, collected by other shops, in a public forum. Good or bad it lets the consumer make a more informed decision. It's a better than the typical "expect midrange power increase" with our header. Right?

Phatron, check out EFI's review/data, and by all means call the sources of these tests. Chris at EFI Logics and/or Robbie at Epic Motorsports can answer any questions you have. I'm a mechanical engineer not a tuner, so they can much better answer your questions and they have no vested interest in selling headers.

No one is doubting the power listed on the dyno sheet.
It's just a matter of simple causation. The dyno numbers are listing an outcome. Outcomes are great, but they never explain cause. Even if you were to do back to back testing against other headers, you would be only comparing outcomes but you wouldn;t be able to derive a cause without other data listed.

It's like grades. If a student gets an A on the test in June but didn't in the previous month, you can say that the grades improved, but you can't say why. Also even if the principal or teacher were to tell me "The student improved because of x," as an educated person I wouldn't listen to what he/she said because I know that without recorded data sets, I'm trusting a person and not facts. But if I were uneducated, I would listen. On that same note, I would also agree that the student did better and feel happy for that student.

And this makes me wonder too, since you are 3MI Racing LLC. It almost sounds like you're angling to make your own product, possibly piggybacking on the design we've been working on for a good portion of this past year (patent pending BTW). If I'm mistaken here I apoligize, and please feel free to set me straight on your intentions.

what I said is a rotated setup. Never mentioned what turbo or app (just an FYI I'm looking to pick up a bugeye wagon as a dd)...my standing mile set up will require a custom manifold, not doubt. Any for the forementioned manifolds will be way to small and your runners, too short.

I'm actually thinkging about closing up the 3MI Racing LLC stuff all together. Really happy with Volvo and have been sending customers to Maxwell Power for a while, as far as builds go. So no worries here. I do plan to do my own manifold yes, but that will be a big boy, one off, kind of deal. Making prototype manifold is a pain in the butt

If you don't want to be involved or don't want me involved, that's fine. I can make my own. I've designed and carried out numerous manifolds, both NA and turbo before...just figured this is easier and more worth my time. Besides, I like helping the community out and like seeing testing done well and properly.

Looks like a bit more boost with your header up top is causing the increase in power. With the Perrin test, it looks like there was a boost leak or a pre-turbo exhaust leak... notice the torque peak is well after 4k RPM. This could also explain the lower boost levels up top.

BTW, I'm not saying your product is not good, but we all have to be very careful about how we run tests like this to make sure they're fair. I don't want this to turn into another Garage GT fiasco .

My leak theories are based on actually physically testing many cars for boost and exhaust leaks and finding major leaks in about 75% of tested cars and smaller leaks in about 90%. These are cars that have been built by "proffesional" shops as well as private parties. Because of this we always pressure test all cars that we work on extensively. No one believes their cars have leaks until they see it for themselves. I believe this sort of test should be common practice and especially so when doing testing and comparisons.

My leak theories are based on actually physically testing many cars for boost and exhaust leaks and finding major leaks in about 75% of tested cars and smaller leaks in about 90%. These are cars that have been built by "proffesional" shops as well as private parties. Because of this we always pressure test all cars that we work on extensively. No one believes their cars have leaks until they see it for themselves. I believe this sort of test should be common practice and especially so when doing testing and comparisons.

My leak theories are based on actually physically testing many cars for boost and exhaust leaks and finding major leaks in about 75% of tested cars and smaller leaks in about 90%. These are cars that have been built by "proffesional" shops as well as private parties. Because of this we always pressure test all cars that we work on extensively. No one believes their cars have leaks until they see it for themselves. I believe this sort of test should be common practice and especially so when doing testing and comparisons.

-- Ed

Ed, while I don't have your data regarding the effects of manifold leaks I can tell you that when we were researching manifold designs we came a cross a lot of "don't do this" material (same as when we designed our oil pan) and I will keep these manufactures nameless. One of those items that we didn't want to deal with was gasket leaks due to poor flange design and/or warping from welding. I've posted a few examples we came across during our what not to do search. one has obvious leaks due to finish and/or warped flange surface the other just has horrible finish that will likely leak at some level too. Of course the 2 bolt flange was never an option for our setup as they are horribly unreliable from a gasket/seal perspective.

Not only a rough time saver finish, but you'll notice the top right hole is ovalized. This is not something you'll NEVER see in a Killer B Header.

Regarding our product, we are not a shop, we're a manufacturer. You'll never find one of our welders installing parts or wrenching on cars one day and welding another. They weld, and only weld. They are welders and know how to spread the heat around to minimize warping. ALL of our flanges are CNC machined on all surfaces to our own spec to provide a flat smooth surface finish. Even at this, a 1/2" flange can still move some, and that's why we grind our flange surface flat as one of the final processes our headers go through.

The last variable we have no control over; who installs the product. Were new OEM gaskets used, torqued to proper spec, etc. That's up to you guys

[...] a change in VE could still result in a shift in a/f. This is because VE defines how efficiently the engine uses the air that it consumes. If you increase VE and keep all other parameters consistent (including airflow), you will inherently see a shift in the a/f.

You define VE very differently than me and the rest of the world. That sounds more like a definition of BSFC (or BS(Air)C, really).

But your explanation still doesn't make sense. If the MAF sensor tells the ECU that the engine is pulling in (for example) 100 grams per second, and if the ECU wants an 11:1 AFR, it's going to inject fuel at a rate of 9 grams per second. Why would changing VE (per your definition or everyone else's) change the AFR?

It doesn't change change the ECU's target AFR, it doesn't change the air flow, it doesn't change the fuel flow.... so why would it change the air-fuel ratio?

this kinda contradicts its self. your saying the MAF can make the corrections and thats it! but then you say the tuner needs to adjust scaling. so ill hold what i said first. the MAF can adjust BUT not much! thats why you cant throw in 1000cc injectors and be ok. why you cant add a CAI, DP, header, UP CBE and be ok. i put on a CAI with no adjustment and shot up to 33MPG. the car was WAY to lean. the AFR and scaling still needs adjusted because the MAF CANT do it all.

There are no contradictions there, but you have much to learn about how MAF-based fueling works.

You seem to be thinking that the MAF sensor's job is to correct for changes in AFR, but that is not the case. The MAF sensor, in conjuction with MAF sensor scaling, tells the ECU how much air the engine is flowing. Period.

The ECU uses that air flow rate, plus its knowledge of the injector characteristics (flow rate and latency) to open the injectors just long enough to inject the appropriate amount of fuel to get the desired AFR.

If the engine starts flowing more air, and the MAF scaling is correct, the ECU still knows how much air the engine is flow, so it can still inject the correct amount of fuel to achieve the desired AFR.